Phd Degree / Doktora

Permanent URI for this collectionhttps://hdl.handle.net/11147/2869

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Author: search.filters.author.Böke, HasanPublisher: search.filters.publisher.Izmir Institute of Technology

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Now showing 1 - 8 of 8
  • Doctoral Thesis
    Evaluation of Stone Deterioration Problems of Anavarza Archaeological Site for the Purpose of Conservation
    (Izmir Institute of Technology, 2021) İpekci, Emre; Böke, Hasan; Aydın, Rozelin; Lubelli, Barbara
    In this study, horasan and lime plasters of Zeyrek Çinili Bath (16th c.) in İstanbul built by Mimar Sinan, considered as the master architect of the Ottoman Empire, were investigated to determine application techniques of plasters, basic physical properties, raw material compositions, microstructural properties and hydraulicity of plasters, mineralogical, chemical compositions of binders, pozzolanic activities of crushed brick aggregates by using standard test methods, binocular microscope, XRD, SEM-EDS and TGA. Multilayered plaster application on the wall surfaces of the inner spaces of the bath was classified as lower level and upper level plasters. The lower level plasters are composed of two horasan plaster layers. The first layer is rough while the second layer is fine. Glazed tiles are adhered on the second layer of the horasan plasters by glazed tile adhesives. Hence, all horasan plasters are original and not repaired. The upper level plasters are composed of a horasan plaster layer with one or two lime plaster layers. The plasters of domes are consisted of a rough horasan plaster layer with one fine lime plaster layer. Horasan plasters used in all spaces of the bath have no significant differences in their physical properties, mineralogical, chemical compositions, microstructural properties, pozzolanicity and hydraulicity. Horasan plasters are high porous and low dense materials. The layers of horasan plasters used in the bath are well adhered to each other. Brick aggregates of horasan plasters have good puzzolanic properties. Hence, most of the horasan plasters are hydraulic.
  • Doctoral Thesis
    Properties of Lime Binders and Aggregates of Roman Mortars in Western Anatolia
    (Izmir Institute of Technology, 2021) Taşcı, Burcu; Böke, Hasan
    In this study, the characteristics of Roman lime mortars taken from a wide area in Western Anatolia were determined in order to understand whether there was a common production technology of lime mortar in the Roman Empire by making a comparison between Europe and Western Anatolia. For this purpose, opus caementicium and opus signinum mortars were collected from twenty-six archaeological sites in Western Anatolia. Basic physical properties, raw material compositions, mineralogical and chemical compositions, mechanical, microstructural, and hydraulic properties of mortars, pozzolanicity and geochemical characteristics of aggregates were identified by SEM-EDS, MIP, XRD, TGA, FTIR analyses, and point load tests. Results showed Roman lime mortars were compact, low dense, and high porous materials. Opus caementicium mortars were grayish with the use of crushed stones, however opus signinum mortars were light brownish due to the use of crushed bricks/tiles. Opus caementicium mortars were used in various types of structures, while opus signinum mortars were generally used in water-related structures. Lime/aggregate ratios of mortars varied between 1:4-3:2 parallel to ideal lime/aggregate written in Roman sources. Despite using high calcium lime in the production of mortars, the compressive strengths of mortars were found compatible with NHL3.5 type of lime due to the use of pozzolanic aggregates which were produced from rhyolite and dacite (silicic rocks). These results indicated that the properties of Roman lime mortars were similar in Western Anatolia and other regions of the Roman Empire. This finding can be evidence of common lime mortar technology produced using similar local sources throughout the Roman Empire.
  • Doctoral Thesis
    Long-Term Protection Efficiency of Biodegradable Polymer Treatments on Limestone
    (Izmir Institute of Technology, 2019) Kaplan, Zişan; Böke, Hasan; Sofuoğlu, Aysun; İpekoğlu, Başak
    Synthetic polymers can be replaced by biodegradable ones as adhesive, water repellents and consolidants in stone conservation to preserve historic buildings from further deterioration. In this study, the long-term stabilities of two biodegradable polymers, polyhydroxybutyrate (PHB) and poly-l-lactide (PLA) and an acrylic polymer (Paraloid B72), which are commonly used in conservation works of artefacts, were evaluated on limestone through an UV lamp-weathering chamber. Chemical and morphological changes induced by accelerated weathering test were followed by Fourier Transform Infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) analysis. The protection efficiencies of the polymers were determined by following the changes in the color, capillary water absorption and static contact angle on the limestone surfaces in accordance with CEN standards developed by the European Committee of Standardization (CEN) for conservation of cultural property. PHB, PLA and Paraloid B72 coatings significantly increased hydrophobicity, decreased capillary water absorption and caused negligible change in the color of the limestone. All polymers showed chemical, physical and optical changes under accelerated weathering conditions. Paraloid B72 decomposed by the reduction of molecular weight, decomposition of ester group and formation of gamma lactones and hydro peroxides. PHB and PLA decomposed with formation of CO2 and hydro peroxide, hydrolysis of ester groups and reduction of the molecular weight. Chemical changes cause to etching, holes, voids, cracks and slight color differentiations on the coatings by chain scission, breaking of polymer bonds and formation of volatile gaseous products. Protection efficiencies of the PLA and PHB polymers almost same as that of the widely used acrylic polymer Paraloid B72. However, PLA and PHB seem to be promising polymers as protective agents due to their reversibility and biodegradability, low chromatic changes, good hydrophobic behavior and good stability to weathering in reducing the effects of outdoor exposure on limestone surfaces.
  • Doctoral Thesis
    Conservation Approaches of Patina Formation on Marble and Travertine Surfaces in the Archaeological Sites
    (Izmir Institute of Technology, 2017) Badur, Fulya; Böke, Hasan; Yalçın, Şerife Hanım
    Patina, which is formed on the stone surfaces of historical buildings and monuments as a result of aging, is considered as a value of the building in the conservation of cultural heritage studies. It should be conserved on calcareous stone surfaces whether or not it represents protective characteristics, since it provides information about previous times. Within this respect, the determination of mineralogical composition, and microstructural and chemical characteristics of patina are critical for the conservation decisions. The aim of this study is to determine the characteristics of yellow patina formation on marble and yellow travertine surfaces to constitute a conservation approach in the archaeological sites. In this study, XRD, FT-IR, SEM-EDX, LIBS and TGA were used to determine the characteristics of yellow patina formation on marble and yellow travertine surfaces in Aizanoi, Aphrodisias, Sardes and Hierapolis. Analysis results indicated that yellow patina is mainly composed of calcium oxalate (whewellite or weddelite) minerals. CaO, MgO, Al2O3, SiO2, P2O5, K2O, SO3, FeO and Na2O were observed on the chemical analyses of the same samples. The results of LIBS and SEM-EDX showed that Ca increases, and other elements decrease from surface to the sound inner parts of the stone due to calcium oxalate and gypsum precipitation and clay deposition on the surfaces. The calcium oxalate patina forms a homogeneous film layer on calcite crystals. It is most likely formed by the reaction of calcite and oxalic acid produced by the biological formations on stone surfaces. It is colorless in original. The yellow color may be related with the FeO and clay deposition on the stone surfaces. The outcomes of the study proved the presence of a protective yellow patina formation on yellow travertine surfaces against the weathering effects of water which cannot be distinguished by naked eye. This patina presents same characteristics with the yellow patina on marble surfaces which should be conserved. The results of this study show that the determination of yellow patina is critical to keep irreversible cleaning interventions away from surfaces especially for the monuments that yellow travertine is used as building materials.
  • Doctoral Thesis
    Determination of Byzantine Wall Painting Techniques in Wester Anatolia
    (Izmir Institute of Technology, 2017) Şerifaki, Kerem; Böke, Hasan
    Wall paintings are the reflections of the lifestyle, sense of art and technology of their own period. Conservation of wall paintings should be considered as a multidisciplinary process which is comprised of documentation, materials characterization, evaluation of deterioration problems and conservation decisions. This study aims to determine the material characteristics and execution techniques of historic wall paintings executed in Byzantine era in western Anatolia. Within this scope, the stratigraphy, mineralogical and chemical composition of the plaster layers; the execution technique, stratigraphy, mineralogical and chemical compositions of paint layers of wall paintings from the substructure of Anaia Church, Başpınar Church and Aigai have been determined by Polarized Light Microscope (PLM), Scanning Electron Microscope coupled with XRay Energy Dispersive System (SEM-EDS), X-ray diffraction analyses (XRD), Fourier transform infrared spectrometry (FT-IR) and Laser Induced Breakdown Spectroscopy (LIBS) analyses. Through the research, pure lime and aggregates in the plasters of Aigai, magnesium rich lime and straw in the plasters of Anaia and Başpınar have been determined. Execution technique used in wall paintings are determined as fresco in Aigai and as secco in Anaia. In Başpınar church painting was started as fresco but completed as secco. Pigments used in paintings are mainly iron oxides for red and yellow, green earth in celadonite and glauconite forms for green, lapis lazuli and Egyptian blue for blue, calcite and kaolin for white and carbon black for grey and black colors. Results of the experimental studies are also evaluated for dating the wall paintings. As a result, studied wall paintings were classified as pre-iconoclastic and post- iconoclastic. Painting technique, pigments and plaster characteristics of wall paintings in western Anatolia in Byzantine period were determined to be similar with the ones in İstanbul, Cappadocia, Balkans, Crete, and Cyprus. Results of this study will guide the conservation efforts of the wall paintings.
  • Doctoral Thesis
    Investigation of the Deterioration Problems of Excavated Andesite Monuments in Archaeological Sites for the Purpose of Conservation
    (Izmir Institute of Technology, 2015) Kaplan, Çağlayan Deniz; Böke, Hasan; Böke, Hasan
    Archaeological sites have to be preserved as the witnesses of the earliest human activities. Determination of deterioration processes of stone monuments in archaeological sites is one of the fundamental phases for their preservation. In this study, deterioration problems of excavated andesites from Aigai and Assos archaeological sites were investigated for the purpose of conservation. Within this intent, visual analysis of the andesite deteriorations was carried out with site surveys in four years intervals and basic physical, petrographic and microstructural properties, mineralogical, elemental and chemical compositions of interior parts and exterior surfaces of the andesites were determined and compared. Visual analyses at the sites show that the progress of andesite deterioration after excavation is insignificant during the four years. The experimental results indicated the slight chemical deterioration of the silica and ferromagnesian minerals and calcium-feldspars through the action of carbon dioxide and water during burial resulted in the formation of clay minerals and calcium carbonate and hematite patinas on the andesite surfaces respectively. Presence of clay minerals promotes physical, chemical and biological deterioration. The experimental results indicated that excavations can be carried out by preventive conservation measures to prevent further andesite deteriorations in open air conditions. As for the preventive conservation measures, the study suggests that the controlled drying of the andesites during excavations has to be supplied, clays on the stone surfaces have to be cleaned but but calcium carbonate layer have to be protected and biocides have to be implemented to prevent the biological formations. Site planning such as drainage to keep the water away from the monuments have to be supplied after their excavations.
  • Doctoral Thesis
    Characteristics of Roman Mortars Produced From Natural and Artificial Pozzolans in Aigai and Nysa
    (Izmir Institute of Technology, 2012) Uğurlu Sağın, Elif; Böke, Hasan
    The use of lime and natural and artificial pozzolans for mortar production were the important contributions of the Romans to the construction history. In this study, characteristics of Roman lime mortars produced by natural and artificial pozzolans from ancient cities of Aigai and Nysa have been determined in order to understand technology of Roman period lime mortars used in Anatolia. Within this scope, basic physical properties, raw material compositions, microstructural and hydraulic properties, mineralogical and chemical compositions of mortars were investigated by SEM-EDS, XRD, XRF, TGA, FTIR and LIBS analysis. A relatively fast and easy method was proposed for the quantitative determination of CaCO3 and SiO2 content in the binder compositions by using FTIR, LIBS, SEM-EDS and XRD analyses. The results indicated that Roman lime mortars either produced by natural or artificial pozzolans were low dense and high porous materials with a high percent of macro pores. Roman lime mortars were mainly produced by using non-hydraulic high calcium lime and pozzolanic aggregates. Lime/aggregate ratios of mortars produced by natural pozzolans were 0.30, and mortars produced by artificial pozzolans were 0.55 respectively. Natural and artificial pozzolans from Aigai and Nysa were found to be produced by using different raw material sources. The method proposed for the quantitative determination of CaCO3 and SiO2 revealed that FTIR, SEM-EDS and LIBS analysis could be safely used to determine the lime and fine silica content in the binders of historic lime mortars. Characteristics of lime mortars used in Anatolia were determined to be similar to the mortars used in Central Roman Empire although wall construction techniques of Anatolian architecture were different from the Central Roman Empire. The knowledge produced on the Roman lime mortar characteristics of Anatolian architecture is important for the conservation of ancient sites in Anatolia and the production of new lime mortars to be used in these sites.
  • Doctoral Thesis
    Climatic Considerations in Traditional Built Environments: the Efect of Natural Ventilation on Thermal Comfort in Alac¸atı, I·zmir, Turkey
    (Izmir Institute of Technology, 2011) Terim, Belgin; Böke, Hasan; Doğan, Fehmi
    The traditional settlements in Turkey are under a growing danger of either destruction and despair or tourism. The urban tissue of historical settlement areas is attractive for touristic activities and vacation programs, but in many of these settlements the tissue is mostly ruined. The main reason of this deformation is the lately defined conservation regulations. The buildings of the old settlements are ruined or fixed with unhealthy methods and the infill or new settlement areas cannot integrate morphologically with the old heritage. The conservation of the buildings in the historical settlements is expensive, so especially in historical settlements close to tourist attraction centers such as şirince and Alaçatı in the Aegean Region, the construction of new buildings to answer the need for new residential building stock increases. The problem in the design of these new dwellings constructed in the empty parcels within the settlement or in the boarders of the settlement is that they do not follow the design principles of the traditional settlements and when they seem to follow the design principles they do that only at the level of image. The objective of this thesis is to evaluate the physical conditions of the old traditional settlement examples, and to compare these data to find out new design criteria for the design of climatically responsive new buildings in these specific areas. To invent a method to evaluate the air pressure change between the open, semiopen, and closed spaces of traditional Turkish houses will be the main goal of this study. The point where this study outstands from the other similar studies is the observation of different housing typology, which needs to be studied with the airflow factor under temperate-hot climate conditions. The houses of Anatolian settlements are mainly not mid-courtyard houses and the semi-open spaces are the most important part of these houses, so the observation of natural ventilation behavior is different from other studies working with different climate areas. Alaçatı, Izmir, TURKEY is chosen as the case study area for this study, because it is one of the fastest growing urban sites in the Aegean Region of Anatolia.